The goal of this paper is to defend the general tenet that time travelers cannot change the past within B-theoretical models of time, independently of how many temporal dimensions there are. Baron (2017) offered a strong argument intended to reach this general conclusion. However, his argument does not cover a peculiar case, i.e. a B-theoretical one-dimensional model of time that allows for the presence of internal times. Loss (2015) used the latter model to argue that time travelers can change the past within such model. We show a way to debunk Loss’s argument, so that the the general tenet about the impossibility of changing the past within B-theoretical models is maintained.